Securing long-term energy supplies for the giant Chinese economic machine dominated the agenda on Tuesday as China's President Hu Jintao made his second visit to oil powerhouse Saudi Arabia.Travelling with a large entourage of Chinese officials and executives, Hu was greeted at Riyadh airport by Saudi King Abdullah for a three-day visit which underscores the growing importance of the relationship between the world's biggest oil exporter and its most populous country."Saudi Arabia is the biggest oil exporter to China. We value the role it plays and look forward to strengthening cooperation in this field," Chinese foreign ministry spokeswoman Jiang Yu said earlier.The visit will also mark the growing investments by Chinese companies in Saudi non-energy sectors, and their interest in taking part in the Saudi government's massive infrastructure development programme.Both countries were stressing their increasing cooperation in fields like health, science and education, and they were expected to sign several accords on trade and other cooperation.During the airport greeting, Hu introduced to King Abdullah 12 Chinese schoolchildren, survivors of the May 2008 earthquake in Sichuan province that killed or left missing 87,000 people.The children offered the king their thanks for his donations in support of the victims and Abdullah gave the children gifts, the official SPA news agency said.Chinese news agency Xinhua, quoting an official statement released at the start of the visit, said talks between Hu and King Abdullah would focus on China-Saudi ties as well as "global and regional issues of common concern, including ways of addressing the international financial crisis."China's trade with Saudi Arabia has more than doubled since 2005, rising 65 percent last year alone to reach 41.8 billion dollars, as oil and gas prices skyrocketed and the Chinese economy required more fuel to keep expanding.